Bonding structure and method of forming same

ABSTRACT

A package includes a first die that includes a first metallization layer, one or more first bond pad vias on the first metallization layer, wherein a first barrier layer extends across the first metallization layer between each first bond pad via and the first metallization layer, and one or more first bond pads on the one or more first bond pad vias, wherein a second barrier layer extends across each first bond pad via between a first bond pad and the first bond pad via, and a second die including one or more second bond pads, wherein a second bond pad is bonded to a first bond pad of the first die.

PRIORITY CLAIM AND CROSS-REFERENCE

This application claims the benefits of U.S. Provisional Application No.62/893,971, filed on Aug. 30, 2019, which application is herebyincorporated herein by reference in its entirety.

BACKGROUND

In wafer-to-wafer bonding technology, various methods have beendeveloped to bond two package components (such as wafers) together. Somewafer bonding methods include fusion bonding, eutectic bonding, directmetal bonding, hybrid bonding, and the like. In fusion bonding, an oxidesurface of a wafer is bonded to an oxide surface or a silicon surface ofanother wafer. In eutectic bonding, two eutectic materials are placedtogether, and a high pressure and a high temperature are applied. Theeutectic materials are hence melted. When the melted eutectic materialssolidify, the wafers bond together. In direct metal-to-metal bonding,two metal pads are pressed against each other at an elevatedtemperature, and the inter-diffusion of the metal pads causes thebonding of the metal pads. In hybrid bonding, the metal pads of twowafers are bonded to each other through direct metal-to-metal bonding,and an oxide surface of one of the two wafers is bonded to an oxidesurface or a silicon surface of the other wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIGS. 1-9 illustrate cross-sectional views of intermediate steps in aprocess for forming a device structure, in accordance with someembodiments.

FIGS. 10-17 illustrate cross-sectional views of intermediate steps in aprocess for forming a die structure, in accordance with someembodiments.

FIGS. 18A, 18B, 19A, 19B, 20A, 20B, and 21 illustrate cross-sectionalviews of packages having die structures, in accordance with someembodiments.

FIGS. 22-26 illustrate cross-sectional views of intermediate steps in aprocess for forming a package structure, in accordance with someembodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

A bonding structure and method is provided, in accordance with someembodiments. Bond pad vias (BPVs) are formed over metal pads in a seriesof processing steps, and then bond pads are formed over the BPVs in asubsequent series of processing steps. By forming the BPVs and the bondpads separately, the metal pads to which the BPVs are connected may beformed closer together and/or having a smaller area. Additionally, theBPVs or the bond pads may also be formed closer together and/or with asmaller area. This can reduce the size of a die or package. Thecorresponding bond pads of two bonded dies may be formed havingdifferent areas such that misalignment between the two dies has littleor no effect on the contact resistance at the connection between thecorresponding bond pads.

FIGS. 1-9 illustrate cross-sectional views of intermediate stages in theformation of a device structure 100 (see FIG. 9), in accordance withsome embodiments. FIG. 1 illustrates a substrate 102, in accordance withsome embodiments. In FIGS. 1-9, multiple device structures 100 areformed on a single substrate 102 and then singulated to form individualdevice structures 100, in accordance with some embodiments. The regionslabeled “100” in FIGS. 1-8 indicate regions where the device structures100 shown in FIG. 9 are formed, and the region labeled “104” indicates ascribe line region 104 between adjacent device structures 100.

The substrate 102 may be a semiconductor substrate, such as a bulksemiconductor, a semiconductor-on-insulator (SOI) substrate, asemiconductor wafer, or the like, which may be doped (e.g., with ap-type or an n-type dopant) or undoped. Generally, a SOI substrateincludes a layer of a semiconductor material formed on an insulatorlayer. The insulator layer may be, for example, a buried oxide (BOX)layer, a silicon oxide layer, or the like. The insulator layer isprovided on a substrate, typically a silicon substrate or a glasssubstrate. Other substrates, such as a multi-layered or gradientsubstrate may also be used. In some embodiments, the semiconductormaterial of the substrate may include silicon; germanium; a compoundsemiconductor including silicon carbide, gallium arsenic, galliumphosphide, indium phosphide, indium arsenide, and/or indium antimonide;an alloy semiconductor including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs,GaInP, and/or GaInAsP; or combinations thereof.

In some embodiments, the substrate 102 and features formed thereon areused to form a device die, integrated circuit die, or the like. In suchembodiments, integrated circuit devices may be formed on the top surfaceof the substrate 102. Exemplary integrated circuit devices may includecomplementary metal-oxide semiconductor (CMOS) transistors, finfield-effect transistors (FinFETs), resistors, capacitors, diodes, thelike, or a combination thereof. The details of the integrated circuitdevices are not illustrated herein. In other embodiments, the substrate102 is used for forming an interposer structure. In such embodiments, noactive devices such as transistors are formed on the substrate 102.Passive devices such as capacitors, resistors, inductors, or the likemay be formed in the substrate 102. The substrate 102 may also be adielectric substrate in some embodiments in which the substrate 102 ispart of an interposer structure. In some embodiments, through vias (notshown) may be formed extending through the substrate 102 in order tointerconnect components on the opposite sides of the substrate 102.

In FIG. 2, an interconnect structure 108 is formed over the substrate102, in accordance with some embodiments. The interconnect structure 108provides routing and electrical connections between devices formed inthe substrate 102, and may be, e.g., a redistribution structure or thelike. The interconnect structure 108 may include a plurality ofinsulating layers 110, which may be inter-metal dielectric (IMD) layers,described in greater detail below. Each of the insulating layers 110includes one or more conductive features 113, which may be metal linesand/or vias formed therein in a metallization layer. In otherembodiments, the metal lines may be, for example, redistribution layers.The conductive features 113 may be electrically connected to the activeand/or passive devices of the substrate 102 by the contacts (not shownin the Figures).

Some portions of the conductive features 113 formed in the topmostinsulating layer 110 of the interconnect structure 108 may be formedhaving relatively larger area than the other conductive features 113within the interconnect structure 108. The conductive features of theinterconnect structure 108 that are formed in the topmost insulatinglayer 110 are separately labeled as metal pads 112 in FIG. 2. The metalpads 112 may be utilized as for connecting subsequently formedconductive features (e.g., conductive pads 118, bond pad vias (BPVs)128, or the like) to the interconnect structure 108. In someembodiments, the conductive features of the topmost insulating layer 110may also comprise metal lines or vias, which are not separately shown inFIG. 2. The metal pads 112 may be formed having a width W1 that isbetween about 2 μm and about 10 μm or having an area that is betweenabout 4 μm² and about 100 μm². Adjacent metal pads 112 may be separatedby a distance D1 that is between about 2 μm and about 20 μm. Otherdimensions or distances are possible. In some cases, the techniquesdescribed herein may allow for metal pads 112 having a smaller width W1or a smaller area. In some cases, the techniques described herein mayallow for forming metal pads 112 that are separated by a smallerdistance D1. By forming a smaller or closer metal pads 112, thedimensions (e.g. the “footprint”) of the device structure 100 may bereduced. Additionally, the routing distance between features may bereduced, which can improve higher speed operation of the devicestructure 100.

In some embodiments, the insulating layers 110 may be formed from alow-k dielectric material having a k-value lower than about 3.0. Theinsulating layers 110 may be formed from an extra-low-k (ELK) dielectricmaterial having a k-value of less than 2.5. In some embodiments, theinsulating layers 110 may be formed from an oxygen-containing and/orcarbon containing low-k dielectric material, Hydrogen SilsesQuioxane(HSQ), MethylSilsesQuioxane (MSQ), the like, or a combination thereof.In some embodiments, some or all of insulating layers 110 are formed ofnon-low-k dielectric materials such as silicon oxide, silicon carbide(SiC), silicon carbonitride (SiCN), silicon oxycarbonitride (SiOCN), orthe like. In some embodiments, etch stop layers (not shown), which maybe formed of silicon carbide, silicon nitride, or the like, are formedbetween insulating layers 110. In some embodiments, the insulatinglayers 110 are formed from a porous material such as SiOCN, SiCN, SiOC,SiOCH, or the like, and may be formed by spin-on coating or a depositionprocess such as plasma enhanced chemical vapor deposition (PECVD), CVD,PVD, or the like. In some embodiments, the interconnect structure 108may include one or more other types of layers, such as diffusion barrierlayers (not shown).

In some embodiments, the interconnect structure 108 may be formed usinga single and/or a dual damascene process, a via-first process, or ametal-first process. In an embodiment, an insulating layer 110 isformed, and openings (not shown) are formed therein using acceptablephotolithography and etching techniques. Diffusion barrier layers (notshown) may be formed in the openings and may include a material such asTaN, Ta, TiN, Ti, CoW, or the like, and may be formed in the openingsusing a deposition process such as CVD, Atomic Layer Deposition (ALD),or the like. A conductive material may be formed in the openings fromcopper, aluminum, nickel, tungsten, cobalt, silver, combinationsthereof, or the like, and may be formed over the diffusion barrierlayers in the openings using an electro-chemical plating process, CVD,ALD, PVD, the like, or a combination thereof. After formation of theconductive material, excess conductive material may be removed using,for example, a planarization process such as CMP, thereby leavingconductive features 113 in the openings of the respective insulatinglayer 110. The process may then be repeated to form additionalinsulating layers 110 and conductive features 113 therein. In someembodiments, the topmost insulating layer 110 and the metal pads 112formed therein may be formed having a thickness greater than a thicknessof the other insulating layers 110 of the interconnect structure 108. Insome embodiments, one or more of the topmost conductive features aredummy metal lines or dummy metal pads 112 that are electrically isolatedfrom the substrate 102.

In FIG. 3, a passivation layer 114 is formed over the interconnectstructure 108, and one or more openings are formed in the passivationlayer 114. The passivation layer 114 may comprise one or more layers ofone or more materials. For example, the passivation layer 114 mayinclude one or more layers of silicon nitride, silicon oxide, siliconoxynitride, the like, or a combination. The passivation layer 114 may beformed using a suitable process such as CVD, PECVD, PVD, ALD, the like,or a combination thereof. In some embodiments, the passivation layer 114may be formed having a thickness greater than a thickness of the topmostinsulating layer 110. The openings in the passivation layer 114 may beformed using a suitable photolithographic and etching process. Forexample, a photoresist may be formed over the passivation layer 114 andpatterned, and then the patterned photoresist used as an etching mask.The passivation layer 114 may be etching using a suitable wet etchingprocess and/or dry etching process. The openings are formed to exposeportions of the metal pads 112 for electrical connection.

In FIG. 4, conductive pads 118 are formed over the passivation layer 114in accordance with some embodiments. One or more conductive pads 118 maybe formed extending through the openings in the passivation layer 114 tomake electrical connection with one or more of the metal pads 112 of theinterconnect structure 108. In some embodiments, the conductive pads 118may be formed by first depositing a blanket layer of a conductivematerial such as aluminum. For example, CVD, PVD, or the like may beused to deposit a layer of aluminum over the passivation layer 114, theopenings, and the metal pads 112. A photoresist layer (not separatelyillustrated) may then be formed over the aluminum layer and the aluminumlayer may be etched to form the conductive pads 118. Conductive pads 118formed from aluminum in this manner may be referred to as “aluminumpads.”

In other embodiments, the conductive pads 118 are formed by firstforming a seed layer over the passivation layer 114 and the openings. Insome embodiments, the seed layer is a metal layer comprising one or morelayers, which may be formed of different materials. The seed layer maybe formed using, for example, PVD or the like. A photoresist is formedand patterned on the seed layer and conductive material is formed in theopenings of the photoresist and on the exposed portions of the seedlayer. In some embodiments, the conductive material may be formed usinga plating process, such as using an electroplating or electrolessplating process, or the like. The conductive material may include one ormore materials such as copper, titanium, tungsten, gold, cobalt, thelike, or a combination thereof. The photoresist and portions of the seedlayer on which the conductive material is not formed are then removedusing, for example, a suitable ashing or stripping process, such asusing an oxygen plasma or the like. Once the photoresist is removed,remaining exposed portions of the seed layer may be removed using anacceptable etching process, such as a wet etching process or a dryetching process. The remaining portions of the seed layer and conductivematerial form the conductive pads 118. The conductive pads 118 may beformed using other techniques in other embodiments, and all suchtechniques are considered within the scope of this disclosure.

In some embodiments, the conductive pads 118 that are electricallyconnected to the interconnect structure 108 may be used as test padsbefore additional processing steps are performed. For example, theconductive pads 118 may be probed as part of a wafer-acceptance-test, acircuit test, a Known Good Die (KGD) test, or the like. The probing maybe performed to verify the functionality of the active or passivedevices of the substrate 102 or the respective electrical connectionswithin the substrate 102 or interconnect structure 108 (e.g., theconductive features 113). The probing may be performed by contacting aprobe needle 119 to the conductive pads 118. The probe needle 119 may bea part of a probe card that includes multiple probe needles 119 which,for example, may be connected to testing equipment.

In some embodiments, the conductive material of the conductive pads 118may be different than the conductive material of the metal pads 112. Forexample, the conductive pads 118 may be aluminum and the metal pads 112may be copper, though other conductive materials may be used. In someembodiments, the conductive pads 118 may have a width W2 between about 2μm and about 30 μm or a length (e.g., perpendicular to the width)between about 20 μm and about 100 μm. In some embodiments, theconductive pads 118 may be separated from an adjacent metal pad 112 by adistance D2 that is between about 2 μm and about 30 μm. The embodimentsdescribed in the present disclosure may allow for a smaller separationdistance between conductive pads 118 and adjacent metal pads 112 withoutincreasing the chance of causing processing defects such as shorts. Inthis manner, the dimensions of the device structure 100 may be reducedwithout decreasing the yield.

Turning to FIG. 5, a dielectric layer 122 is formed over the passivationlayer 114 and the conductive pads 118. The dielectric layer 122 may beformed from one or more layers of one or more dielectric materials, suchas silicon oxide, silicon nitride, silicon oxynitride, siliconcarbonitride, SiOC, SiOCH, SiCH, the like, or a combination thereof. Insome embodiments, the dielectric layer 122 may be formed fromphosphosilicate glass (PSG), borosilicate glass (BSG), boron-dopedphosphosilicate glass (BPSG), fluorine-doped silicate glass (FSG),tetraethyl orthosilicate (TEOS), the like, or a combination thereof. Thedielectric layer 122 may be formed using a deposition process such asCVD, PECVD, PVD, ALD, the like, or a combination thereof. The dielectriclayer 122 may be formed to have a thickness greater than a thickness ofthe conductive pads 118 so that the material of the dielectric layer 122laterally surrounds the conductive pads 118, and so that the dielectriclayer 122 may be planarized (see below) without exposing the conductivepads 118.

In FIG. 6, openings 124 are formed in the dielectric layer 122, inaccordance with some embodiments. The openings 124 expose the metal pads112 to allow subsequently formed bond pad vias (BPVs) 128 to makeelectrical connection to the interconnect structure 108 through themetal pads 112. In some embodiments, the openings 124 expose theconductive pads 118, and the BPVs 128 make electrical connection to theinterconnect structure 108 through the conductive pads 118 (see e.g.,FIGS. 20A-21). The openings 124 may be formed using acceptablephotolithography and etching techniques. For example, thephotolithography process may include forming a photoresist (not shown)over the dielectric layer 122, patterning the photoresist with openingscorresponding to the openings 124, extending the openings 124 throughthe dielectric layer 122 and the passivation layer 114 to expose themetal pads 112, and then removing the photoresist.

Turning to FIG. 7, bond pad vias (BPVs) 128 are formed in the openings124, in accordance with some embodiments. The BPVs 128 may have similardimensions as the openings 124 in which they are formed, and may have asimilar shape (e.g., have a tapered profile). In some embodiments, theformation of the BPVs 128 includes first forming a first barrier layer127 within the openings 124. The first barrier layer 127 may be, forexample, a liner, a diffusion barrier layer, an adhesion layer, or thelike. The first barrier layer 127 may include one or more layerscomprising titanium, titanium nitride, tantalum, tantalum nitride, thelike, or combinations thereof. The first barrier layer 127 may bedeposited as a blanket layer over the dielectric layer 122 and withinthe openings 124. The first barrier layer 127 may be formed using adeposition process such as CVD, PECVD, PVD, the like, or combinationsthereof.

The formation of the BPVs 128 may include depositing a conductivematerial over the first barrier layer 127. The conductive material mayinclude cobalt, copper, a copper alloy, titanium, silver, gold,tungsten, aluminum, nickel, the like, or combinations thereof. Theconductive material of the BPVs 128 may be formed using a depositionprocess such as CVD, PECVD, PVD, the like, or combinations thereof. Insome embodiments, the conductive material of the BPVs 128 is formed bydepositing a seed layer (not shown) over the first barrier layer 127,which may include copper, a copper alloy, titanium, or the like, andthen filling the remainder of the openings 124 using, for example, aplating process, an electro-less plating process, or the like.

After forming the conductive material, a planarization process, such asa grinding process, a chemical-mechanical polish (CMP) process, or thelike may be performed to remove excess material from a surface of thedielectric layer 122. The remaining first barrier layer 127 andconductive material thus form the BPVs 128. In this manner, the BPVs 128may be formed using a single damascene process. In some embodiments,some “dummy” BPVs 128 (not shown) may be formed without havingelectrical connection to the metal pads 112. In some cases, dummy BPVs128 may reduce uneven loading and improve surface planarity after theplanarization step that removes excess material.

The BPVs 128 may have a width W3 between about 1 μm and about 5 μm,although other widths are possible. In some embodiments, the BPVs 128may have a tapered profile, such as having an upper width W3A that isbetween about 1 μm and about 5 μm and a lower width W3B that is betweenabout 0.5 μm and about 4 μm. The width W3 of a BPV 128 may be betweenabout 50% and about 95% of the width W1 of its associated metal pad 112(see FIG. 2). The BPVs 128 may be formed such that the lateral distanceD3 between a sidewall of a BPV 128 and the adjacent sidewall of itsassociated metal pad 112 between about 1 μm and about 5 μm, althoughother distances are possible. In some cases, by forming the BPVs 128separately from the bond pads 316 (see FIG. 17 below), the metal pads112 may be formed having a smaller width W1 that is closer in size tothe width W3 of the BPVs 128. This can allow for the lateral separationbetween features such as conductive pads 118, metal pads 112, BPVs 128,and/or bond pads 316 (see FIG. 17) to be reduced. Additionally, thedistance D3 may be reduced, allowing the BPVs 128 to be formed closer tothe edges of the metal pads 112.

Turning to FIG. 8, a bond layer 126 is formed over the dielectric layer122. The bond layer 126 may be formed from one or more layers of one ormore dielectric materials, and may comprise a silicon-containingmaterial such as silicon oxide. In some embodiments, the bond layer 126may comprise one or more layers of other materials such as siliconnitride, silicon oxynitride, silicon carbonitride, SiOC, SiOCH, SiCH,the like, or a combination thereof. The bond layer 126 may be formedusing a deposition process such as CVD, PECVD, PVD, ALD, the like, or acombination thereof. In some embodiments, the bond layer 126 comprises adifferent material than the dielectric layer 122.

In FIG. 9, a singulation process is performed along scribe line regions104 to separate adjacent device structures 100. The singulation processmay include a dicing process, a sawing process, a laser process, thelike, or a combination thereof. In some embodiments, singulated devicestructures 100 that were probed and found to be Known Good Die (KGD),described above in FIG. 4, are used in subsequent process steps to formdie structures 300 (see FIG. 15).

FIGS. 10-17 illustrate cross-sectional views of intermediate stages inthe formation of a die structure 300 (see FIG. 17) that incorporates thedevice structure 100, in accordance with some embodiments. In FIG. 10,the device structure 100 is bonded to a carrier 202, in accordance withsome embodiments. The carrier 202 may be a silicon substrate (e.g., asilicon wafer), a glass substrate, an organic substrate (e.g. a panel),or the like. In some embodiments, one or more layers such as oxidelayers or etch stop layers may be formed on the carrier 202, which areshown in FIGS. 10-13 as layers 204. In some embodiments, a dielectriclayer 208 is formed on the carrier 202, and optional alignment features210 may be formed within the dielectric layer 208. In some embodiments,the dielectric layer 208 may be formed from silicon oxide, PSG, BSG,BPSG, FSG, silicon nitride, the like, or a combination thereof. Thedielectric layer 208 may be formed using a deposition process such asCVD, PECVD, PVD, the like, or a combination thereof. In someembodiments, the dielectric layer 208 is formed of a softer materialthan the subsequently formed bond layer 212, and may act as a bufferlayer for absorbing stress. In accordance with some embodiments, thealignment features 210 are metal features formed in the dielectric layer208. The alignment features 210 may be used as alignment marks foraligning the subsequent placement (e.g., using a pick-and-place process)and the bonding of device structure 100. The alignment features 210 maybe formed, for example, using a damascene process or another suitableprocess.

A bond layer 212 may then be formed over the dielectric layer 208. Thebond layer 212 may be formed from one or more layers of one or moredielectric materials such as silicon oxide or the like. The bond layer212 may be formed using a deposition process such as CVD, PECVD, PVD,ALD, the like, or a combination thereof. The bond layer 212 may comprisethe same material as the bond layer 126 or a different material than thebond layer 126. The combination of the carrier 202, the dielectric layer208, and the bond layer 212 is referred to herein as the first carrierstructure 250.

Still referring to FIG. 10, the device structure 100 is placed on thefirst carrier structure 250 using, for example, a pick-and-placeprocess. The alignment features 210 may be used during placement toalign the device structure 100. The device structure 100 is placed suchthat the bond layer 126 and the bond layer 212 are in contact. A plasmacleaning process or a wet chemical cleaning process may be performed onthe bond layer 126 or the bond layer 212 prior to placement in order toactivate the surfaces. After placement, the bond layer 126 of the devicestructure 100 is bonded to the bond layer 212 using direct bonding(e.g., “fusion bonding” or “dielectric-to-dielectric bonding”), whichmay, for example, form Si—O—Si bonds between the bond layer 126 and thebond layer 212. In some embodiments, the bond layer 126 and the bondlayer 212 may be pressed against each other to facilitate the bondingprocess. The bonding process may be performed at room temperature (e.g.,at a temperature of from about 21° C. to about 25° C.), although highertemperatures may be used. In some embodiments, an anneal is performedafter bonding, which may strengthen the bond between the bond layer 126and the bond layer 212.

Turning to FIG. 11, dielectric regions 214 (otherwise known as “gap-filldielectric” regions) are formed surrounding the device structure 100, inaccordance with some embodiments. In some embodiments, the dielectricregions 214 may be formed from one or more layers of silicon oxide, PSG,BSG, BPSG, FSG, silicon nitride, the like, or a combination thereof. Thedielectric material of the dielectric regions 214 may be formed using adeposition process such as CVD, PECVD, PVD, the like, or a combinationthereof. In some embodiments, the dielectric material may be formed bydispensing a flowable dielectric material (e.g., a flowable oxide), andthen curing the flowable dielectric material. The flowable dielectricmaterial may be dispensed using a lamination process, a spin-coatingprocess, or the like. After forming the dielectric material, aplanarization process (e.g., a CMP or grinding process) may be performedto remove excess dielectric material from over the substrate 102 of thedevice structure 100, forming the dielectric regions 214. Afterperforming the planarization process, the dielectric regions 214 and thesubstrate 102 may have level (e.g., coplanar) surfaces. In someembodiments, the planarization process also thins the substrate 102.

Turning to FIG. 12, a dielectric layer 220 is formed on the dielectricregions 214 and substrate 102. In some embodiments, optional alignmentfeatures 222 are formed within the dielectric layer 220. In someembodiments, the dielectric layer 220 may be formed from silicon oxide,PSG, BSG, BPSG, FSG, silicon nitride the like, or a combination thereof.The dielectric layer 220 may be formed using a deposition process suchas CVD, PECVD, PVD, the like, or a combination thereof. In someembodiments, the dielectric layer 220 is formed of a softer materialthan the subsequently formed bond layer 224, and may act as a bufferlayer for absorbing stress. In accordance with some embodiments, thealignment features 222 are metal features formed in the dielectric layer220. The alignment features 222 may be formed, for example, using adamascene process or another suitable process.

A bond layer 224 may then be formed over the dielectric layer 220. Thebond layer 224 may be formed from one or more layers of one or moredielectric materials such as silicon oxide or the like. The bond layer224 may be formed from similar materials or using similar techniques asdescribed above for bond layer 126.

Turning to FIG. 13, the structure is flipped over and bonded to a secondcarrier structure 350, and then the first carrier structure 250 isremoved, in accordance with some embodiments. The second carrierstructure 350 may include, for example, a bond layer 306 formed over acarrier 302. The carrier 302 may be a silicon substrate (e.g., a siliconwafer), a glass substrate, an organic substrate (e.g. a panel), or thelike. The bond layer 306 may be formed from one or more layers of one ormore dielectric materials, and may comprise a silicon-containingmaterial such as silicon oxide, silicon nitride, silicon oxynitride,silicon carbonitride, SiOC, SiOCH, SiCH, the like, or a combinationthereof. The bond layer 306 may be formed using a deposition processsuch as CVD, PECVD, PVD, ALD, the like, or a combination thereof. Thebond layer 306 may comprise the same material as the bond layer 224 or adifferent material than the bond layer 224.

Still referring to FIG. 13, the structure is flipped over, and the bondlayer 224 is placed on the bond layer 306 of the second carrierstructure 350, in accordance with some embodiments. A plasma cleaningprocess or a wet chemical cleaning process may be performed on the bondlayer 224 or the bond layer 306 prior to placement in order to activatethe surfaces. After placement, the bond layer 224 is bonded to the bondlayer 306 using direct bonding (e.g., “fusion bonding” or“dielectric-to-dielectric bonding”), which may, for example, formSi—O—Si bonds between the bond layer 224 and the bond layer 306. In someembodiments, the bond layer 224 and the bond layer 306 may be pressedagainst each other to facilitate the bonding process. The bondingprocess may be performed at room temperature (e.g., at a temperature offrom about 21° C. to about 25° C.), although higher temperatures may beused. In some embodiments, an anneal is performed after bonding, whichmay strengthen the bond between the bond layer 224 and the bond layer306.

In FIG. 14, the first carrier structure 250 and bond layer 126 areremoved, in accordance with some embodiments. In some embodiments, aplanarization process (e.g., a CMP or grinding process) may be performedto remove the carrier 202, the dielectric layer 208, the bond layer 212,and the bond layer 126. As shown in FIG. 14, the planarization processmay expose the BPVs 128 and the dielectric layer 122. Portions of thedielectric regions 214 are also removed by the planarization process,such that surfaces of the remaining dielectric regions 214 are levelwith the dielectric layer 122 and BPVs 128. In some embodiments, one ormore etching processes (e.g., dry etching processes or wet etchingprocesses) may be used to remove portions of the first carrier structure250 prior to performing the planarization process. In some embodiments,an etching process may be stopped by a layer such as the bond layer 212,the dielectric layer 208, or an etch stop layer within the carrier 202(if present).

Turning to FIG. 15, a bonding layer 312 is formed over the dielectricregions 214, the dielectric layer 122, and the BPVs 128. The bondinglayer 312 may be formed from one or more layers of one or moredielectric materials such as silicon oxide or the like. The bondinglayer 312 may be formed from similar materials or using similartechniques as described above for bond layer 126 or bond layer 224. Insome embodiments, the bonding layer 312 is formed having a thicknessbetween about 0.2 μm and about 1 μm. The thickness of the bonding layer312 may determine the thickness of the subsequently formed bond pads 316(see FIG. 17).

In FIG. 16, openings 314 are formed in the bonding layer 312, inaccordance with some embodiments. The openings 314 expose the BPVs 128to allow subsequently formed bond pads 316 to make electrical connectionto the interconnect structure 108 through the BPVs 128. The openings 314may be formed using acceptable photolithography and etching techniques.For example, the photolithography process may include forming aphotoresist (not shown) over the bonding layer 312, patterning thephotoresist with openings corresponding to the openings 314, extendingthe openings 314 through the bonding layer 312 to expose the BPVs 128,and then removing the photoresist.

Turning to FIG. 17, bond pads 316 are formed in the openings 314 to forma die structure 300, in accordance with some embodiments. In someembodiments, the formation of the bond pads 316 includes first forming asecond barrier layer 315 within the openings 314. The second barrierlayer 315 may be, for example, a liner, a diffusion barrier layer, anadhesion layer, or the like. The second barrier layer 315 may includeone or more layers comprising titanium, titanium nitride, tantalum,tantalum nitride, the like, or combinations thereof. The second barrierlayer 315 may be deposited as a blanket layer over the bonding layer 312and within the openings 314. The second barrier layer 315 may be formedusing a deposition process such as CVD, PECVD, PVD, the like, orcombinations thereof. The second barrier layer 315 may be formed frommaterial(s) similar to the first barrier layer 127, in some embodiments.As shown in FIG. 17, because the BPVs 128 are formed in a separateprocess step prior to formation of the bond pads 316, each secondbarrier layer 315 extends over the top of a BPV 218, which may includeextending over top surfaces of the first barrier layer 127. In thismanner, the first barrier layer 127 of a BPVs 128 and the second barrierlayer 315 of a bond pads 316 are formed separately, rather than the BPVs128 and the bond pads 316 sharing a single, continuous barrier layerformed in a single step.

The formation of the bond pads 316 may include depositing a conductivematerial over the second barrier layer 315. The conductive material mayinclude, for example, copper or a copper alloy. The conductive materialmay comprise other materials such as titanium, silver, gold, tungsten,aluminum, nickel, cobalt, the like, or combinations thereof. Theconductive material of the bond pads 316 may be formed using adeposition process such as CVD, PECVD, PVD, the like, or combinationsthereof. In some embodiments, the conductive material of the bond pads316 is formed by depositing a seed layer (not shown) over the secondbarrier layer 315, which may include copper, a copper alloy, titanium,or the like, and then filling the remainder of the openings 314 using,for example, a plating process, an electro-less plating process, or thelike. The bond pads 316 may be formed from material(s) similar to theBPVs 128, in some embodiments.

After forming the conductive material, a planarization process, such asa grinding process, a chemical-mechanical polish (CMP) process, or thelike may be performed to remove excess material from a surface of thebonding layer 312. The remaining second barrier layer 315 and conductivematerial thus form the bond pads 316. In this manner, the bond pads 316may be formed using a single damascene process. In some embodiments,some “dummy” bond pads 316 (not shown) may be formed without havingelectrical connection to the BPVs 128 and/or the metal pads 112. In somecases, dummy bond pads 316 may reduce uneven loading and improve surfaceplanarity after the planarization step that removes excess material.

In some embodiments, the bond pads 316 may have a width W4 between about0.2 μm and about 5 μm, although other widths are possible. In someembodiments, the width W4 of a bond pad 316 may be between about 120%and about 200% of the width W3 of its associated BPV 128 (see FIG. 7).In some embodiments, the bond pads 316 may be formed such that thelateral distance D4 between a sidewall of a bond pad 316 and theadjacent sidewall of its associated BPV 128 between about 0.5 μm andabout 2 μm, although other distances are possible. In some embodiments,the lateral separation between adjacent bond pads 316 may be a distanceD5 that is between about 2 μm and about 7 μm. In some cases, by formingthe BPVs 128 separately from the bond pads 316 as described herein, thebond pads 316 may be formed having a smaller separation distance D5. Insome cases, by forming the BPVs 128 in a separate process step than thebond pads 316, the lateral separation (e.g., pitch) between featuressuch as conductive pads 118, metal pads 112, BPVs 128, and/or bond pads316 and the sizes of such features can be reduced without increasing therisk of electrical shorts or other process defects.

Turning to FIGS. 18A-B, a package 500 is shown comprising the first diestructure 300 and a second die structure 400 that are bonded together,in accordance with some embodiments. FIG. 18B shows a package 500similar to that shown for FIG. 18A, but for illustrative purposes somefeatures in FIG. 18B are shown with a greater alignment offset than inFIG. 18A. The first die structure 300 of the package 500 may be similarto the die structure 300 described for FIG. 17. In some embodiments, thesecond die structure 400 comprises dielectric regions 402 (otherwiseknown as “gap-fill dielectric” regions), a device structure 440, abonding layer 412, and one or more bond pads 410. The second diestructure 400 shown in FIGS. 18A-B is an example, and the second diestructure 400 or components thereof (e.g., the device structure 440) maybe other structures or other types of structures than shown withoutdeviating from the scope of the present disclosure.

The device structure 440 may be similar to the device structure 100described previously. For example, the device structure 440 may includea substrate 442 similar to the substrate 102, which may includeintegrated circuit devices formed thereon. In some embodiments, throughsubstrate vias (TSVs) 446 may extend through the substrate 442. The TSVs446 may be formed by, for example, forming openings extending throughthe substrate 442 using a suitable photolithography and etching process.The openings may then be filled by a conductive material such as copperor the like, which may be formed using a suitable process such as aplating process. In some embodiments, the device structure 440 includesmetal pads 444 or conductive pads 450, which may be similar to the metalpads 112 or the conductive pads 118 of the device structure 100,respectively.

The dielectric regions 402 may be similar to the dielectric regions 214described previously, such as being formed from silicon oxide or thelike. The bonding layer 412 may be formed from one or more layers of oneor more dielectric materials such as silicon oxide or the like. Thebonding layer 412 may be formed from similar materials or using similartechniques as described above for bond layer 126, bond layer 224, orbonding layer 312. The bond pads 410 may be formed from a conductivematerial such as copper, a copper alloy, or the like. The bond pads 410may also include a barrier layer (not shown). The bond pads 410 may beformed from similar material(s) or using similar techniques as describedabove for the bond pads 316, in some embodiments.

In some embodiments, the bond pads 410 may have a width W5 between about1 μm and about 5 μm, although other widths are possible. In someembodiments, the width W5 of a bond pad 410 may be between about 95% andabout 150% of the width W4 of its associated bond pad 316. In thismanner, the width W5 of the bond pads 410 may be larger than the widthW4 of the bond pads 316. After bonding the bond pads 410 to the bondpads 316, the bond pads 410 may laterally extend beyond the bond pads316, as shown in FIG. 18. FIG. 18A shows bond pads 410 approximatelycentered on bond pads 316, but in other cases, some lateral misalignmentbetween a bond pad 410 and a bond pad 316 may be present. A misalignmentmay be due to, for example, pick-and-place overlay shift duringplacement of the second die structure 400 on the first die structure300. For example, in FIG. 18B, a bond pad 410 is shown as misaligned toa bond pad 316 by a distance S1. The distance Si corresponds to thelateral offset between the center of the bond pad 410 (e.g., at half ofthe width W5) and the center of the bond pad 316 (e.g., at half of thewidth W4). In some cases, forming bond pads 410 that are wider than bondpads 316 can increase the chance that the entirety of the top surfacesof the bond pads 316 are bonded to the bond pads 410 if any misalignmentbetween the first die structure 300 and the second die structure 400 ispresent. In some cases, the maximum misalignment distance (e.g., S1) forwhich the entire surface of a bond pad 316 remains bonded is given bythe difference between the width W5 of the bond pad 410 and the width W4of the bond pad 316. Bonding the entire top surfaces of the bond pads316 can reduce contact resistance between the bond pads 316 and the bondpads 410, and thus can improve electrical performance of the package500. In this manner, undesirable effects due to misalignment can bereduced by forming bond pads 410 having a larger width than that of thebond pads 316.

Other misalignments are possible. For example, FIG. 18A shows bond pads316 approximately centered on BPVs 128, but in other cases, some lateralmisalignment between a bond pad 316 and a BPV 128 may be present. Forexample, in FIG. 18B, a bond pad 316 is shown as misaligned to a BPV 128by a distance S2. The distance S2 corresponds to the lateral offsetbetween the center of the bond pad 316 (e.g., at half of the width W4)and the center of the BPV 128 (e.g., at half of the width W3). In somecases, forming bond pads 316 that are wider than the BPVs 128 canincrease the chance that the entirety of the top surfaces of the BPVs128 are covered by the overlying bond pads 316 if any misalignmentbetween bond pads 316 and BPVs 128 is present. In some cases, themaximum misalignment distance (e.g., S2) for which the entire topsurface of a BPV 128 remains covered by an overlying bond pad 316 isgiven by the difference between the width W4 of the bond pad 316 and thewidth W3 of the BPV 128. Covering the entire top surfaces of the BPVs128 can reduce contact resistance between the bond pads 316 and the BPVs128, and thus can improve electrical performance of the package 500. Inthis manner, undesirable effects due to misalignment can be reduced byforming bond pads 316 having a larger width than that of the BPVs 128.

The second die structure 400 may also include a redistribution structure452 including dielectric layers 460 and 462 and metallization patterns454 and 456. The redistribution structure 452 may be designed to connectthe various features, such as the device structure 440 and any throughvias 408 (described below) to form functional circuitry. Themetallization patterns may also be referred to as redistribution layersor redistribution lines. More or fewer dielectric layers andmetallization patterns may be formed in the redistribution structure 452than shown. If fewer dielectric layers and metallization patterns are tobe formed, steps and process discussed below may be omitted. If moredielectric layers and metallization patterns are to be formed, steps andprocesses discussed below may be repeated.

As an example to form the redistribution structure 452, themetallization pattern 454 may first be formed. To form the metallizationpattern 454, a seed layer is formed over device structure 400 and thedielectric regions 402. In some embodiments, the seed layer is a metallayer, which may be a single layer or a composite layer comprising aplurality of sub-layers formed of different materials. In someembodiments, the seed layer comprises a titanium layer and a copperlayer over the titanium layer. The seed layer may be formed using, forexample, PVD or the like. A photoresist is then formed and patterned onthe seed layer. The photoresist may be formed by spin coating or thelike and may be exposed to light for patterning. The pattern of thephotoresist corresponds to the metallization pattern 454. The patterningforms openings through the photoresist to expose the seed layer. Aconductive material is then formed in the openings of the photoresistand on the exposed portions of the seed layer. The conductive materialmay be formed by plating, such as electroplating or electroless plating,or the like. The conductive material may comprise a metal, like copper,titanium, tungsten, aluminum, or the like. The combination of theconductive material and underlying portions of the seed layer form themetallization pattern 454. The photoresist and portions of the seedlayer on which the conductive material is not formed are removed. Thephotoresist may be removed by an acceptable ashing or stripping process,such as using an oxygen plasma or the like. Once the photoresist isremoved, exposed portions of the seed layer are removed, such as byusing an acceptable etching process, such as by wet or dry etching.

The dielectric layer 460 then deposited on the metallization pattern454, the device 440, and the dielectric regions 402. In someembodiments, the dielectric layer 460 is formed of a photo-sensitivematerial such as PBO, polyimide, BCB, or the like, which may bepatterned using a lithography mask. The dielectric layer 460 may beformed by spin coating, lamination, CVD, the like, or a combinationthereof. The dielectric layer 460 is then patterned. The patterningforms openings exposing portions of the metallization pattern 454. Thepatterning may be by an acceptable process, such as by exposing thedielectric layer 124 to light when the dielectric layer 460 is aphoto-sensitive material or by etching using, for example, ananisotropic etch. If the dielectric layer 460 is a photo-sensitivematerial, the dielectric layer 460 can be developed after the exposure.

The metallization pattern 456 is then formed on the patterned dielectriclayer 460 and extending into the openings in the dielectric layer 460 tocontact the metallization pattern 454. The metallization pattern 456 maybe formed in a manner similar to the metallization pattern 454, and maybe formed of a similar material as the metallization pattern 454. Thedielectric layer 462 may be formed on the metallization pattern 456 andthe dielectric layer 460. The dielectric layer 462 may be formed in amanner similar to the dielectric layer 460, and may be formed of asimilar material as the dielectric layer 460. The redistributionstructure 452 may be formed using other materials or techniques thandescribed in this example.

In some embodiments, the second die structure 400 includes one or morethrough vias 408 that extends partially or completely through the seconddie structure 400 to connect the redistribution structure 452 or otherfeatures on opposite sides of the second die structure 400. A second diestructure 400 may include zero, one, two, or more than two through vias408, in some embodiments. The second die structure 400 shown in FIG. 18also includes underbump metallizations (UBMs) 418 and externalconnectors 420 formed on the redistribution structure 452, in accordancewith some embodiments. The UBMs 418 provide electrical connection toconductive features within the second die structure 400, and theexternal connectors 420 (e.g., solder balls, bumps, or the like) areformed on the UBMs 418. In some embodiments, the UBMs 418 are not formedprior to forming the external connectors 420, and in some embodiments,the external connectors 420 are not formed on the second die structure400.

The second die structure 400 shown is an illustrative example, and itwill be appreciated that all suitable die, chips, devices, or the likeare considered within the scope of this disclosure. In some embodiments,the second die structure 400 may be formed in a manner similar to firstdie structure 300. For example, the second die structure 400 may includeBPVs (not individually labeled) formed in a first process step, and thebond pads 410 may be formed over the BPVs in a separate process step,similar to as described above for FIG. 7 and FIG. 17.

In some embodiments, the second die structure 400 is bonded to the firstdie structure 300 to form package 500 using, e.g., direct bonding orhybrid bonding. Before performing the bonding, a surface treatment maybe performed on the second die structure 400 or the first die structure300 in order to activate the surfaces. In some embodiments, the surfacetreatment includes a plasma treatment. The plasma treatment may beperformed in a vacuum environment (e.g., a vacuum chamber, not shown).The process gas used for generating the plasma may be ahydrogen-containing gas, which includes a first gas including hydrogen(H₂) and argon (Ar), a second gas including H₂ and nitrogen (N₂), or athird gas including H₂ and helium (He). The plasma treatment may also beperformed using pure or substantially pure H₂, Ar, or N₂ as the processgas, which treats the surfaces of the bond pads 316/410 and the bondinglayers 312/412. The second die structure 400 or the first die structure300 may be treated with the same surface treatment process, or withdifferent surface treatment processes, or not treated. In someembodiments, the second die structure 400 or the first die structure 300may be cleaned after the surface treatment. Cleaning may includeperforming e.g., a chemical cleaning and a de-ionized watercleaning/rinse.

Next, a pre-bonding process may be performed with the second diestructure 400 and the first die structure 300. The second die structure400 is placed on the first die structure 300 using, for example, apick-and-place process. The alignment features 222 may be used duringplacement to align the second die structure 400. The second diestructure 400 and the first die structure 300 are aligned such that thebonding pads 410 and/or the through vias 408 of the second die structure400 are aligned to the bonding pads 316 of the first die structure 300.After the alignment, the second die structure 400 and the first diestructure 300 may be pressed against each other. The pressing force maybe less than about 5 Newtons per die in some embodiments, although agreater or smaller force may also be used. The pre-bonding process maybe performed at room temperature (e.g., at a temperature of from about21° C. to about 25° C.), although higher temperatures may be used. Thepre-bonding time may be shorter than about 1 minute, in someembodiments.

After the pre-bonding, the bonding layer 412 of the second die structure400 and the bonding layer 312 of the first die structure 300 are bondedto each other, forming package 500. The bond between the bonding layers312/412 may be strengthened in a subsequent annealing step. The package500 may be annealed at a temperature of from about 300° C. to about 400°C. and for a period of time between about 1 hour and about 2 hours, forexample. During the annealing, metals in the bond pads 316 and 410 maydiffuse such that metal-to-metal bonds are also formed. Bonds betweenthe bond pads 316 and corresponding through vias 408 may be formedsimilarly. Hence, the resulting bonds between the first die structure300 and the second die structure 400 may be hybrid bonds. In someembodiments, after the annealing, no material interface is presentbetween the bond pads 316 and the corresponding bond pads 410 or throughvias 408. In some embodiments, a singulation process may be performed onthe package 500 after bonding.

FIG. 18A shows a through via 408 approximately centered on a bond pad316, but in other cases, some lateral misalignment between a through via408 and a bond pad 316 may be present. For example, in FIG. 18B, athrough via 408 is shown as misaligned to a bond pad 316 by a distanceS3. The distance S3 corresponds to the lateral offset between the centerof the through via 408 and the center of the bond pad 316 (e.g., at halfof the width W4). In some cases, forming bond pads 316 that are widerthan the through vias 408 can increase the chance that the entirety ofthe surfaces of the through vias 408 are bonded to the correspondingbond pads 316 if any misalignment between bond pads 316 and through vias408 is present. In some cases, the maximum misalignment distance (e.g.,S3) for which the entire surface of a through via 408 remains bonded toa corresponding bond pad 316 is given by the difference between thewidth W4 of the bond pad 316 and the width of the through via 408.

FIGS. 19A-B, 20A-B, and 21 illustrate packages 510, 520, and 530, eachincluding a first die structure 300 bonded to a second die structure400, in accordance with some embodiments. For each of the packages 510,520, and 530, the first die structure 300 and the second die structure400 may be similar to the first die structure 300 and the second diestructure 400 as described for FIGS. 18A-B, and the first die and thesecond die may be bonded in a similar manner as described for FIGS.18A-B. All such variations of forming packages are contemplated withinthe scope of this disclosure.

Turning first to FIG. 19A, the package 510 is similar to package 500shown in FIG. 18A, except that the bond pads 410 of the second diestructure 400 have a width W6 that is smaller than the width W4 (seeFIG. 17) of the bond pads 316 of the first die structure 300. FIG. 19Bshows a package 510 similar to that shown for FIG. 19A, but forillustrative purposes some features in FIG. 19B are shown with a greateralignment offset than in FIG. 19A. In some embodiments, the bond pads410 may have a width W6 between about 1.5 μm and about 5 μm, althoughother widths are possible. In some embodiments, the width W6 of a bondpad 410 may be between about 40% and about 90% of the width W4 of itsassociated bond pad 316. In this manner, the width W6 of the bond pads410 may be smaller than the width W4 of the bond pads 316. After bondingthe bond pads 410 to the bond pads 316, the bond pads 316 may laterallyextend beyond the bond pads 410, as shown in FIG. 19A.

FIG. 19A shows a bond pad 410 approximately centered on a bond pad 316,but in other cases, some lateral misalignment between a bond pad 410 anda bond pad 316 may be present. For example, in FIG. 19B, a bond pad 410is shown as misaligned to a bond pad 316 by a distance S4. The distanceS4 corresponds to the lateral offset between the center of the bond pad410 (e.g., at half of the width W6) and the center of the bond pad 316(e.g., at half of the width W4). In some cases, forming bond pads 410that have a smaller width than bond pads 316 can increase the chancethat the entirety of the top surfaces of the bond pads 410 are bonded tothe bond pads 316 if any misalignment between the first die structure300 and the second die structure 400 is present. In some cases, themaximum misalignment distance (e.g., S4) for which the entire surface ofa bond pad 410 remains bonded is given by the difference between thewidth W6 of the bond pad 410 and the width W4 of the bond pad 316.Bonding the entire bonding surfaces of the bond pads 410 can reducecontact resistance between the bond pads 316 and the bond pads 410, andthus can improve electrical performance of the package 510. In thismanner, undesirable effects due to misalignment can be reduced byforming bond pads 410 having a smaller width than that of the bond pads316.

Turning next to FIGS. 20A-B and 21, the packages 520 and 530 are similarto package 500 shown in FIGS. 18A-B, except that the BPVs 128 contactthe conductive pads 118 and make electrical connection to theinterconnect structure 108 through the conductive pads 118. FIGS. 20A-Bshow a package 520 in which the bond pads 410 of the second diestructure 400 have a width that is larger than the bond pads 316 of thefirst die structure 300, similar to package 500 shown in FIGS. 18A-B.FIG. 20B shows a package 520 similar to that shown for FIG. 20A, but forillustrative purposes some features in FIG. 20B are shown with a greateralignment offset than in FIG. 20A. FIG. 21 shows a package 530 in whichthe bond pads 410 of the second die structure 400 have a width that issmaller than the bond pads 316 of the first die structure 300, similarto package 510 shown in FIG. 19. Misalignment similar to that describedfor FIGS. 18A-B, 19A-B, and 20A may also be present for the package 530described for FIG. 21, but is not shown in a separate figure.

The conductive pads 118 that contact the BPVs 128 may be formed in asimilar manner as the conductive pad 118 shown above for FIGS. 3-4. Forexample, the passivation layer 114 may be patterned to expose the metalpads 112, and then the conductive pads 118 formed over the metal pads112. The BPVs 128 may be formed in a similar manner as the BPVs 128shown in FIGS. 6-7. For example, openings 124 may be formed in thedielectric layer 122, except that the openings expose the conductivepads 118 instead of the metal pads 112. The first barrier layer 127 andthe conductive material of the BPVs 128 may then be formed in theopenings 124 as described for FIG. 7. As shown in FIGS. 20A-B and 21,some conductive pads 118 may not be connected to a BPV 128. In someembodiments, the lateral separation between adjacent conductive pads 118may be a distance D6 that is between about 2 μm and about 100 μm.

In some cases, by forming the BPVs 128 separately from the bond pads 316as described herein, the conductive pads 118 may be formed having asmaller size and/or separation distance D6. In some cases, by formingthe BPVs 128 to contact the conductive pads 118, the BPVs 128 may beformed having a smaller size and smaller separation distance. Forexample, the shallower depth of the openings 124 to contact theconductive pads 118 may allow for more accurate photolithographicpatterning. In some embodiments, conductive pads 118 that are formed tobe contacted by BPVs 128 may be formed having a smaller width thanconductive pads 118 that are not contacted by BPVs 128. For example, theconductive pads 118 that are not probed may be formed having a smallerwidth. In some embodiments, the conductive pads 118 that are formed tobe contacted by BPVs 128 may have a width W2′ that is between about 1%and about 90% smaller than the width W2 of the other conductive pads118.

FIG. 20A shows a BPV 128 approximately centered on a conductive pad 118,but in other cases, some lateral misalignment between a BPV 128 and aconductive pad 118 may be present. For example, in FIG. 20B, a BPV 128is shown as misaligned to a conductive pad 118 by a distance S5. Thedistance S5 corresponds to the lateral offset between the center of theBPV 128 (e.g., at half of the width W3) and the center of the conductivepad 118 (e.g., at half of the width W2′). In some cases, by forming theBPVs 128 in a separate process step than the bond pads 316 allows forBPVs 128 to be formed having a smaller width (e.g., W3). Forming BPVs128 that have a smaller width (e.g., a smaller width than correspondingconductive pads 118) can increase the chance that the entirety of thesurfaces of the BPVs 128 are bonded to the conductive pads 118 if anymisalignment is present. In some cases, the maximum misalignmentdistance (e.g., S5) for which the entire surface of a BPV 128 remainsbonded is given by the difference between the width W3 of the BPV 128and the width W2′ of the corresponding conductive pas 118. Bonding theentire bonding surfaces of the BPVs 128 can reduce contact resistancebetween the BPVs 128 and the conductive pads 118, and thus can improveelectrical performance of the package 520. In this manner, the size orpitch of some conductive features of a bonded package can be reducedwithout increasing the risk of undesirable effects due to misalignmentor other process defects.

FIGS. 22-26 illustrate intermediate steps in the formation of a packagestructure 1000 including a package 600, in accordance with someembodiments. FIG. 22 illustrates a first die structure 300 and a seconddie structure 400 that have been bonded into a package 600. The firstdie structure 300 and a second die structure 400 may be similar to thefirst die structure 300 or the second die structure 400 describedpreviously for FIGS. 17-21. The package 600 may be similar to packages500, 510, 520, or 530 described previously for FIGS. 18A-21, except thatexternal connectors 420 are not formed on the second die structure 400.As shown in FIG. 22, the package 600 includes contact pads 602 formed onthe second die structure 400, which allow for electrical connections tobe made to the package 600.

FIG. 22 also illustrates a carrier substrate 721 with an adhesive layer723 and a polymer layer 725 over the adhesive layer 723. In someembodiments, the carrier substrate 721 includes, for example, siliconbased materials, such as glass or silicon oxide, or other materials,such as aluminum oxide, combinations of any of these materials, or thelike. The carrier substrate 721 may be planar in order to accommodate anattachment of devices such as the package 600. The adhesive layer 723 isplaced on the carrier substrate 721 in order to assist in the adherenceof overlying structures (e.g., the polymer layer 725). In someembodiments, the adhesive layer 723 may include a light to heatconversion (LTHC) material or an ultra-violet glue which loses itsadhesive properties when exposed to ultra-violet light. However, othertypes of adhesives, such as pressure sensitive adhesives, radiationcurable adhesives, epoxies, combinations of these, or the like, may alsobe used. The adhesive layer 723 may be placed onto the carrier substrate721 in a semi-liquid or gel form, which is readily deformable underpressure.

The polymer layer 725 is placed over the adhesive layer 723 and isutilized in order to provide protection to the package 600. In someembodiments, the polymer layer 725 may be polybenzoxazole (PBO),although any suitable material, such as polyimide or a polyimidederivative, may alternatively be utilized. The polymer layer 725 may beplaced using, e.g., a spin-coating process to a thickness of betweenabout 2 μm and about 15 μm, such as about 5 μm, although any suitablemethod and thickness may alternatively be used.

In some embodiments, through-vias such as through-dielectric vias (TDVs)727 are formed over the polymer layer 725. In some embodiments, a seedlayer (not shown) is first formed over the polymer layer 725. The seedlayer is a thin layer of a conductive material that aids in theformation of a thicker layer during subsequent processing steps. In someembodiments, the seed layer may include a layer of titanium about 500 Åthick followed by a layer of copper about 3,000 Å thick. The seed layermay be created using processes such as sputtering, evaporation, or PECVDprocesses, depending upon the desired materials. Once the seed layer isformed, a photoresist (not shown) may be formed and patterned over theseed layer. The TDVs 727 are then formed within the patternedphotoresist. In some embodiments, the TDVs 727 include one or moreconductive materials, such as copper, tungsten, other conductive metals,or the like, and may be formed, for example, by electroplating,electroless plating, or the like. In some embodiments, an electroplatingprocess is used wherein the seed layer and the photoresist are submergedor immersed in an electroplating solution. Once the TDVs 727 have beenformed using the photoresist and the seed layer, the photoresist may beremoved using a suitable removal process. In some embodiments, a plasmaashing process may be used to remove the photoresist, whereby thetemperature of the photoresist may be increased until the photoresistexperiences a thermal decomposition and may be removed. However, anyother suitable process, such as a wet strip, may alternatively beutilized. The removal of the photoresist may expose the underlyingportions of the seed layer. Once the TDVs 727 have been formed, exposedportions of the seed layer are then removed, for example, using a wet ordry etching process. The TDVs 727 may be formed to a height of betweenabout 180 μm and about 200 μm, with a critical dimension of about 190 μmand a pitch of about 300 μm.

After forming the TDVs 727, the package 600 is attached onto the polymerlayer 725. In some embodiments, the package 600 may be placed using,e.g. a pick-and-place process. However, any suitable method of placingthe package 600 may be utilized.

FIG. 23 illustrates an encapsulation of the package 600 and the TDVs 727with an encapsulant 729. The encapsulant 729 may be a molding compoundsuch as a resin, polyimide, PPS, PEEK, PES, a heat resistant crystalresin, combinations of these, or the like. FIG. 24 illustrates athinning of the encapsulant 729 in order to expose the TDVs 727 and thepackage 600. The thinning may be performed, e.g., using a CMP process oranother process. The thinning of the encapsulant 729 may expose thecontact pads 602 of the package 600.

FIG. 25 illustrates a formation of a redistribution structure 800 withone or more layers over the encapsulant 729. In some embodiments, theredistribution structure 800 may be formed by initially forming a firstredistribution passivation layer 801 over the encapsulant 729. In someembodiments, the first redistribution passivation layer 801 may bepolybenzoxazole (PBO), although any suitable material, such as polyimideor a polyimide derivative, such as a low temperature cured polyimide,may alternatively be utilized. The first redistribution passivationlayer 801 may be placed using, e.g., a spin-coating process to athickness of between about 5 μm and about 17 μm, such as about 7 μm,although any suitable method and thickness may alternatively be used.

Once the first redistribution passivation layer 801 has been formed,first redistribution vias 803 may be formed through the firstredistribution passivation layer 801 in order to make electricalconnections to the package 600 and the TDVs 727. For example, the firstredistribution vias 803 may be formed to make electrical contact withthe contact pads 602. In some embodiments the first redistribution vias803 may be formed by using a damascene process, a dual damasceneprocess, or another process. After the first redistribution vias 803have been formed, a first redistribution layer 805 is formed over and inelectrical connection with the first redistribution vias 803. In someembodiments the first redistribution layer 805 may be formed byinitially forming a seed layer (not shown) of a titanium copper alloythrough a suitable formation process such as CVD or sputtering. Aphotoresist (also not shown) may then be formed to cover the seed layer,and the photoresist may then be patterned to expose those portions ofthe seed layer that are located where the first redistribution layer 805is desired to be located.

Once the photoresist has been formed and patterned, a conductivematerial, such as copper, may be formed on the seed layer through adeposition process such as plating. The conductive material may beformed to have a thickness of between about 1 μm and about 10 μm, suchas about 4 μm. However, while the material and methods discussed aresuitable to form the conductive material, these materials are merelyexemplary. Any other suitable materials, such as AlCu or Au, and anyother suitable processes of formation, such as CVD or PVD, mayalternatively be used to form the first redistribution layer 805.

After the first redistribution layer 805 has been formed, a secondredistribution passivation layer 807 may be formed and patterned to helpisolate the first redistribution layer 805. In some embodiments thesecond redistribution passivation layer 807 may be similar to the firstredistribution passivation layer 801, such as by being a positive tonePBO, or may be different from the first redistribution passivation layer801, such as by being a negative tone material such as a low-temperaturecured polyimide. The second redistribution passivation layer 807 may beplaced to a thickness of about 7 μm. Once in place, the secondredistribution passivation layer 807 may be patterned to form openingsusing, e.g., a photolithographic masking and etching process or, if thematerial of the second redistribution passivation layer 807 isphotosensitive, exposing and developing the material of the secondredistribution passivation layer 807. However, any suitable material andmethod of patterning maybe utilized.

After the second redistribution passivation layer 807 has beenpatterned, a second redistribution layer 809 may be formed to extendthrough the openings formed within the second redistribution passivationlayer 807 and make electrical connection with the first redistributionlayer 805. In some embodiments the second redistribution layer 809 maybe formed using materials and processes similar to the firstredistribution layer 805. For example, a seed layer may be applied andcovered by a patterned photoresist, a conductive material such as coppermay be applied onto the seed layer, the patterned photoresist may beremoved, and the seed layer may be etched using the conductive materialas a mask. In some embodiments the second redistribution layer 809 isformed to a thickness of about 4 μm. However, any suitable material orprocess of manufacture may be used.

After the second redistribution layer 809 has been formed, a thirdredistribution passivation layer 811 is applied over the secondredistribution layer 809 in order to help isolate and protect the secondredistribution layer 809. In some embodiments the third redistributionpassivation layer 811 may be formed of similar materials and in asimilar fashion as the second redistribution passivation layer 807 to athickness of about 7 μm. For example, the third redistributionpassivation layer 811 may be formed of PBO or a low-temperature curedpolyimide that has been applied and patterned as described above withrespect to the second redistribution passivation layer 1007. However,any suitable material or process of manufacture may be utilized.

After the third redistribution passivation layer 811 has been patterned,a third redistribution layer 813 may be formed to extend through theopenings formed within the third redistribution passivation layer 811and make electrical connection with the second redistribution layer 809.In some embodiments the third redistribution layer 813 may be formedusing materials and processes similar to the first redistribution layer805. For example, a seed layer may be applied and covered by a patternedphotoresist, a conductive material such as copper may be applied ontothe seed layer, the patterned photoresist may be removed, and the seedlayer may be etched using the conductive material as a mask. In someembodiments the third redistribution layer 813 is formed to a thicknessof 5 μm. However, any suitable material or process of manufacture may beused.

After the third redistribution layer 813 has been formed, a fourthredistribution passivation layer 815 may be formed over the thirdredistribution layer 813 in order to help isolate and protect the thirdredistribution layer 813. In some embodiments the fourth redistributionpassivation layer 815 may be formed of similar materials and in asimilar fashion as the second redistribution passivation layer 807. Forexample, the fourth redistribution passivation layer 815 may be formedof PBO or a low-temperature cured polyimide that has been applied andpatterned as described above with respect to the second redistributionpassivation layer 807. In some embodiments the fourth redistributionpassivation layer 815 is formed to a thickness of about 8 μm. However,any suitable material or process of manufacture may be utilized.

In other embodiments, the redistribution vias and redistribution layersof the redistribution structure 800 may be formed using a damasceneprocess, such as a dual-damascene process. For example, a firstredistribution passivation layer may be formed over the encapsulant 729.The first redistribution passivation layer is then patterned using oneor more photolithographic steps to form both openings for vias andopenings for conductive lines within the first redistributionpassivation layer. A conductive material may be formed in the openingsfor vias and the openings for conductive lines to form the firstredistribution vias and the first redistribution layer. Additionalredistribution passivation layers may be formed over the firstredistribution passivation layer, and additional sets of redistributionvias and conductive lines may be formed in the additional redistributionpassivation layers as described for the first redistribution passivationlayer, forming the redistribution structure 800. This or othertechniques may be used to form the redistribution structure 800.

FIG. 25 additionally illustrates a formation of underbump metallizations819 and third external connectors 817 to make electrical contact withthe third redistribution layer 813. In some embodiments the underbumpmetallizations 819 may each comprise three layers of conductivematerials, such as a layer of titanium, a layer of copper, and a layerof nickel. However, one of ordinary skill in the art will recognize thatthere are many suitable arrangements of materials and layers, such as anarrangement of chrome/chrome-copper alloy/copper/gold, an arrangement oftitanium/titanium tungsten/copper, or an arrangement ofcopper/nickel/gold, that are suitable for the formation of the underbumpmetallizations 819. Any suitable materials or layers of material thatmay be used for the underbump metallizations 819 are fully intended tobe included within the scope of the embodiments.

In some embodiments, the underbump metallizations 819 are created byforming each layer over the third redistribution layer 813 and along theinterior of the openings through the fourth redistribution passivationlayer 815. The forming of each layer may be performed using a platingprocess, such as electrochemical plating, although other processes offormation, such as sputtering, evaporation, or PECVD process, may beused depending upon the desired materials. The underbump metallizations819 may be formed to have a thickness of between about 0.7 μm and about10 μm, such as about 5 μm.

In some embodiments the third external connectors 817 may be placed onthe underbump metallizations 819 and may be a ball grid array (BGA)which comprises a eutectic material such as solder, although anysuitable materials may alternatively be used. In some embodiments inwhich the third external connectors 817 are solder balls, the thirdexternal connectors 817 may be formed using a ball drop method, such asa direct ball drop process. In another embodiment, the solder balls maybe formed by initially forming a layer of tin through any suitablemethod such as evaporation, electroplating, printing, solder transfer,and then performing a reflow in order to shape the material into thedesired bump shape. Once the third external connectors 817 have beenformed, a test may be performed to ensure that the structure is suitablefor further processing.

FIG. 26 illustrates a bonding of a device package 900 to the TDVs 727through the polymer layer 725. Prior to bonding the device package 900,the carrier substrate 721 and the adhesive layer 723 are removed fromthe polymer layer 725. The polymer layer 725 is also patterned to exposethe TDVs 727. In some embodiments, the polymer layer 725 may bepatterned using, e.g., a laser drilling method. In such a method aprotective layer, such as a light-to-heat conversion (LTHC) layer or ahogomax layer (not separately illustrated) is first deposited over thepolymer layer 725. Once protected, a laser is directed towards thoseportions of the polymer layer 725 which are desired to be removed inorder to expose the underlying TDVs 727. During the laser drillingprocess the drill energy may be in a range from 0.1 mJ to about 30 mJ,and a drill angle of about 0 degree (perpendicular to the polymer layer725) to about 85 degrees to normal of the polymer layer 725. In someembodiments the patterning may be formed to form openings over the TDVs727 to have a width of between about 100 μm and about 300 μm, such asabout 200 μm.

In another embodiment, the polymer layer 725 may be patterned byinitially applying a photoresist (not individually illustrated) to thepolymer layer 725 and then exposing the photoresist to a patternedenergy source (e.g., a patterned light source) so as to induce achemical reaction, thereby inducing a physical change in those portionsof the photoresist exposed to the patterned light source. A developer isthen applied to the exposed photoresist to take advantage of thephysical changes and selectively remove either the exposed portion ofthe photoresist or the unexposed portion of the photoresist, dependingupon the desired pattern, and the underlying exposed portion of thepolymer layer 725 are removed with, e.g., a dry etch process. However,any other suitable method for patterning the polymer layer 725 may beutilized.

In some embodiments, the device package 900 includes a substrate 902 andone or more stacked dies 910 (e.g., 910A and 910B) coupled to thesubstrate 902. Although one set of stacked dies 910A/910B isillustrated, in other embodiments, a plurality of stacked dies 910 (eachhaving one or more stacked dies) may be disposed side-by-side coupled toa same surface of the substrate 902. The substrate 902 may be made of asemiconductor material such as silicon, germanium, diamond, or the like.In some embodiments, compound materials such as silicon germanium,silicon carbide, gallium arsenic, indium arsenide, indium phosphide,silicon germanium carbide, gallium arsenic phosphide, gallium indiumphosphide, combinations of these, and the like, may also be used.Additionally, the substrate 902 may be a silicon-on-insulator (SOI)substrate. Generally, an SOI substrate includes a layer of asemiconductor material such as epitaxial silicon, germanium, silicongermanium, SOI, silicon germanium on insulator (SGOI), or combinationsthereof. The substrate 902 is, in one alternative embodiment, based onan insulating core such as a fiberglass reinforced resin core. Oneexample core material is fiberglass resin such as FR4. Alternatives forthe core material include bismaleimide-triazine (BT) resin, oralternatively, other printed circuit board (PCB) materials or films.Build up films such as Ajinomoto build-up film (ABF) or other laminatesmay be used for substrate 902.

The substrate 902 may include active and passive devices (not shown). Awide variety of devices such as transistors, capacitors, resistors,combinations of these, and the like may be used to generate thestructural and functional requirements of the design for the devicepackage 900. The devices may be formed using any suitable methods.

The substrate 902 may also include metallization layers or conductivevias (not shown). The metallization layers may be formed over the activeand passive devices and are designed to connect the various devices toform functional circuitry. The metallization layers may be formed ofalternating layers of dielectric (e.g., low-k dielectric material) andconductive material (e.g., copper) with vias interconnecting the layersof conductive material and may be formed through any suitable process(such as deposition, damascene, dual damascene, or the like). In someembodiments, the substrate 902 is substantially free of active andpassive devices.

The substrate 902 may have bond pads 904 on a first side of thesubstrate 902 to couple to the stacked dies 910, and bond pads 906 on asecond side of the substrate 902, the second side being opposite thefirst side of the substrate 902, to couple to the external connections901. In some embodiments, the bond pads 904 and 906 are formed byforming recesses (not shown) into dielectric layers (not shown) on thefirst and second sides of the substrate 902. The recesses may be formedto allow the bond pads 904 and 906 to be embedded into the dielectriclayers. In other embodiments, the recesses are omitted as the bond pads904 and 906 may be formed on the dielectric layer. In some embodiments,the bond pads 904 and 906 include a thin seed layer (not shown) made ofcopper, titanium, nickel, gold, palladium, the like, or a combinationthereof. The conductive material of the bond pads 904 and 906 may bedeposited over the thin seed layer. The conductive material may beformed by an electro-chemical plating process, an electroless platingprocess, CVD, atomic layer deposition (ALD), PVD, the like, or acombination thereof. In an embodiment, the conductive material of thebond pads 904 and 906 is copper, tungsten, aluminum, silver, gold, thelike, or a combination thereof.

In an embodiment, the bond pads 904 and bond pads 906 are UBMs thatinclude three layers of conductive materials, such as a layer oftitanium, a layer of copper, and a layer of nickel. Other arrangementsof materials and layers, such as an arrangement of chrome/chrome-copperalloy/copper/gold, an arrangement of titanium/titanium tungsten/copper,or an arrangement of copper/nickel/gold, may be utilized for theformation of the bond pads 904 and 906. Any suitable materials or layersof material that may be used for the bond pads 904 and 906 are fullyintended to be included within the scope of the current application. Insome embodiments, the conductive vias extend through the substrate 902and couple at least one of the bond pads 904 to at least one of the bondpads 906.

In the illustrated embodiment, the stacked dies 910 are coupled to thesubstrate 902 by wire bonds 912, although other connections may be used,such as conductive bumps. In an embodiment, the stacked dies 910 arestacked memory dies. For example, the stacked dies 910 may be memorydies such as low-power (LP) double data rate (DDR) memory modules, suchas LPDDR1, LPDDR2, LPDDR3, LPDDR4, or the like memory modules.

The stacked dies 910 and the wire bonds 912 may be encapsulated by amolding material 914. The molding material 914 may be molded on thestacked dies 910 and the wire bonds 912, for example, using compressionmolding. In some embodiments, the molding material 914 is a moldingcompound, a polymer, an epoxy, silicon oxide filler material, the like,or a combination thereof. A curing process may be performed to cure themolding material 914. The curing process may be a thermal curing, a UVcuring, the like, or a combination thereof.

In some embodiments, the stacked dies 910 and the wire bonds 912 areburied in the molding material 914, and after the curing of the moldingmaterial 914, a planarization step, such as a grinding, is performed toremove excess portions of the molding material 914 and provide asubstantially planar surface for the device package 900.

In some embodiments, external connections 901 may be formed to providean external connection between the device package 900 and, e.g., theTDVs 727. The external connections 901 may be contact bumps such asmicrobumps or controlled collapse chip connection (C4) bumps and maycomprise a material such as tin, or other suitable materials, such assilver or copper. In some embodiments in which the external connections901 are tin solder bumps, the external connections 901 may be formed byinitially forming a layer of tin through any suitable method such asevaporation, electroplating, printing, solder transfer, ball placement,or the like, to a thickness of, e.g., about 100 μm. Once a layer of tinhas been formed on the structure, a reflow is performed in order toshape the material into the desired bump shape.

Once the external connections 901 have been formed, the externalconnections 901 are aligned with and placed over the TDVs 727, and abonding is performed. For example, in some embodiments in which theexternal connections 901 are solder bumps, the bonding process maycomprise a reflow process whereby the temperature of the externalconnections 901 is raised to a point where the external connections 901will liquefy and flow, thereby bonding the device package 900 to theTDVs 727 once the external connections 901 resolidify. An encapsulant903 may be formed to encapsulate and protect the device package 900. Theencapsulant 903 may extend between the polymer layer 725 and the devicepackage 900 and may be an underfill in some embodiments. In this manner,a package structure 1000 may be formed.

Embodiments may achieve advantages. By forming the bond pad vias (BPVs)and the bond pads of a die in two separate processing steps, the sizeand/or separation (e.g., pitch) of features such as metal lines,conductive pads, the BPVs, and/or the bond pads may be reduced. Forexample, by forming the BPVs in a first photolithography and etchingstep, the BPVs may be formed closer to other features such as conductivepads (e.g., aluminum pads) without an increased chance of processdefects such as electrical shorts. In this manner, the size of a die ora package incorporating the die may be reduced. Additionally, therouting density of the die or the package may be increased. In somecases, a first bond pad of a first die may be formed such that itsentire bonding surface is bonded to the corresponding second bond pad ofa second die, even when misalignment occurs during the bonding process.For example, the first bond pad of the first die may have a width thatis smaller than the second bond pad, so the entire bonding surface ofthe first bond pad remains contacting the second bond pad even with somemisalignment present between the first bond pad and the second bond pad.In this manner, a package incorporating bonded dies may have improvedcontact resistance between bonded pads when misalignment occurs.

In an embodiment, a device includes an interconnect structure over asemiconductor substrate, the interconnect structure including firstconductive pads, a first dielectric layer over the interconnectstructure, bond pad vias within the first dielectric layer, each bondpad via of the bond pad vias including a first barrier layer extendingalong sidewalls of the first dielectric layer and over a firstconductive pad of the first conductive pads, and a first conductivematerial over the first barrier layer, wherein a top surface of thefirst conductive material and a top surface of the first barrier layerare coplanar, a second dielectric layer over the first dielectric layer,and first bond pads within the second dielectric layer, each first bondpad including a second barrier layer extending along sidewalls of thesecond dielectric layer and on the first conductive material and thefirst barrier layer of a first bond pad via of the bond pad vias,wherein the second barrier layer fully covers the top surface of thefirst conductive material and the top surface of the first barrier layerof the first bond pad via, and a second conductive material over thesecond barrier layer. In an embodiment, the device further includes athird dielectric layer extending over sidewalls of the first dielectriclayer, the interconnect structure, and the semiconductor substrate. Inan embodiment, the second dielectric layer extends over the thirddielectric layer and the first dielectric layer. In an embodiment, thedevice further includes an aluminum pad within the first dielectriclayer, wherein the aluminum pad contacts a first conductive pad of thefirst conductive pads. In an embodiment, a bond pad via contacts thealuminum pad. In an embodiment, the device further includes apassivation layer extending over the first conductive pads, the bond padvias extending through the passivation layer. In an embodiment, adjacentfirst conductive pads are laterally separated by a distance that isbetween 2 μm and 20 μm. In an embodiment, the second barrier layerincludes titanium, titanium nitride, tantalum, or tantalum nitride.

In an embodiment, a package includes a first die that includes a firstmetallization layer, one or more first bond pad vias on the firstmetallization layer, wherein a first barrier layer extends across thefirst metallization layer between each first bond pad via and the firstmetallization layer, and one or more first bond pads on the one or morefirst bond pad vias, wherein a second barrier layer extends across eachfirst bond pad via between a first bond pad and the first bond pad via,and a second die including one or more second bond pads, wherein asecond bond pad is bonded to a first bond pad of the first die. In anembodiment, the first die includes a first bonding layer, the first bondpad is disposed within the first bonding layer, the second die comprisesa second bonding layer, the second bond pad is disposed within thesecond bonding layer, and the first bonding layer is bonded to thesecond bonding layer. In an embodiment, a width of the first bond pad isbetween 95% and 150% of a width of the second bond pad. In anembodiment, a width of the second bond pad is between 95% and 150% of awidth of the first bond pad. In an embodiment, the second die furtherincludes a through via, wherein the through via is bonded to the firstbond pad of the first die. In an embodiment, the package furtherincludes a conductive pad on the first metallization layer, wherein theconductive pad comprises a different conductive material than the one ormore first bond pad vias. In an embodiment, the conductive pad islaterally separated from an adjacent first bond pad via by a distancethat is between 2 μm and 100 μm.

In an embodiment, a method includes forming an interconnect structure ona top surface of a semiconductor substrate, the interconnect structureincluding a first conductive pad, forming a first dielectric layer overthe interconnect structure, etching the first dielectric layer to form afirst opening exposing the first conductive pad, depositing a firstbarrier layer within the first opening in the first dielectric layer,depositing a first conductive material within the first opening and onthe first barrier layer, forming a second dielectric layer over thefirst dielectric layer, etching the second dielectric layer to form asecond opening exposing the first conductive material, depositing asecond barrier layer within the second opening in the second dielectriclayer, depositing a second conductive material within the second openingand on the second barrier layer, and bonding a semiconductor die to thesecond dielectric layer, the semiconductor die including a bonding layerand a bond pad, wherein the bonding bonds the bonding layer of thesemiconductor die to the second dielectric layer and bonds the bond padof the semiconductor die to the second conductive material. In anembodiment, the method includes, after depositing the first conductivematerial, forming a sacrificial layer over the first dielectric layerand the first conductive material, attaching the sacrificial layer to afirst carrier structure, thinning the semiconductor substrate, andremoving the first carrier structure and the sacrificial layer, whereinthe second dielectric layer is formed over the first dielectric layerafter the sacrificial layer is removed. In an embodiment, the methodincludes forming a passivation layer over the interconnect structure andforming a conductive pad over the passivation layer, wherein the firstdielectric layer is formed over the conductive pad and the passivationlayer. In an embodiment, the bond pad of the semiconductor die has alateral width that is less than that of the second conductive material.In an embodiment, the bond pad of the semiconductor die has a lateralwidth that is greater than that of the second conductive material.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A device comprising: an interconnect structureover a semiconductor substrate, the interconnect structure comprising aplurality of first conductive pads; a first dielectric layer over theinterconnect structure; a plurality of bond pad vias within the firstdielectric layer, each bond pad via of the plurality of bond pad viascomprising: a first barrier layer extending along sidewalls of the firstdielectric layer and over a first conductive pad of the plurality offirst conductive pads; and a first conductive material over the firstbarrier layer, wherein a top surface of the first conductive materialand a top surface of the first barrier layer are coplanar; a seconddielectric layer over the first dielectric layer; and a plurality offirst bond pads within the second dielectric layer, each first bond padof the plurality of first bond pads comprising: a second barrier layerextending along sidewalls of the second dielectric layer and on thefirst conductive material and the first barrier layer of a first bondpad via of the plurality of bond pad vias, wherein the second barrierlayer fully covers the top surface of the first conductive material andthe top surface of the first barrier layer of the first bond pad via;and a second conductive material over the second barrier layer.
 2. Thedevice of claim 1, further comprising a third dielectric layer extendingover sidewalls of the first dielectric layer, the interconnectstructure, and the semiconductor substrate.
 3. The device of claim 2,wherein the second dielectric layer extends over the third dielectriclayer and the first dielectric layer.
 4. The device of claim 1, furthercomprising an aluminum pad within the first dielectric layer, whereinthe aluminum pad contacts a first conductive pad of the plurality offirst conductive pads.
 5. The device of claim 4, wherein a bond pad viaof the plurality of bond pad vias contacts the aluminum pad.
 6. Thedevice of claim 1, further comprising a passivation layer extending overthe plurality of first conductive pads, the plurality of bond pad viasextending through the passivation layer.
 7. The device of claim 1,wherein adjacent first conductive pads of the plurality of firstconductive pads are laterally separated by a distance that is between 2μm and 20 μm.
 8. The device of claim 1, wherein the second barrier layercomprises titanium, titanium nitride, tantalum, or tantalum nitride. 9.A package, comprising: a first die comprising: a first metallizationlayer; one or more first bond pad vias on the first metallization layer,wherein a first barrier layer extends across the first metallizationlayer between each first bond pad via and the first metallization layer;and one or more first bond pads on the one or more first bond pad vias,wherein a second barrier layer extends across each first bond pad viabetween a first bond pad and the first bond pad via; and a second diecomprising one or more second bond pads, wherein a second bond pad isbonded to a first bond pad of the first die.
 10. The package of claim 9,wherein the first die comprises a first bonding layer, wherein the firstbond pad is disposed within the first bonding layer, wherein the seconddie comprises a second bonding layer, wherein the second bond pad isdisposed within the second bonding layer, and wherein the first bondinglayer is bonded to the second bonding layer.
 11. The package of claim 9,wherein a width of the first bond pad is between 95% and 150% of a widthof the second bond pad.
 12. The package of claim 9, wherein a width ofthe second bond pad is between 95% and 150% of a width of the first bondpad.
 13. The package of claim 9, wherein the second die furthercomprises a through via, wherein the through via is bonded to the firstbond pad of the first die.
 14. The package of claim 9, furthercomprising a conductive pad on the first metallization layer, whereinthe conductive pad comprises a different conductive material than theone or more first bond pad vias.
 15. The package of claim 14, whereinthe conductive pad is laterally separated from an adjacent first bondpad via by a distance that is between 2 μm and 100 μm.
 16. A methodcomprising: forming an interconnect structure on a top surface of asemiconductor substrate, the interconnect structure comprising a firstconductive pad; forming a first dielectric layer over the interconnectstructure; etching the first dielectric layer to form a first openingexposing the first conductive pad; depositing a first barrier layerwithin the first opening in the first dielectric layer; depositing afirst conductive material within the first opening and on the firstbarrier layer; forming a second dielectric layer over the firstdielectric layer; etching the second dielectric layer to form a secondopening exposing the first conductive material; depositing a secondbarrier layer within the second opening in the second dielectric layer;depositing a second conductive material within the second opening and onthe second barrier layer; and bonding a semiconductor die to the seconddielectric layer, the semiconductor die comprising a bonding layer and abond pad, wherein the bonding bonds the bonding layer of thesemiconductor die to the second dielectric layer and bonds the bond padof the semiconductor die to the second conductive material.
 17. Themethod of claim 16, further comprising: after depositing the firstconductive material, forming a sacrificial layer over the firstdielectric layer and the first conductive material; attaching thesacrificial layer to a first carrier structure; thinning thesemiconductor substrate; and removing the first carrier structure andthe sacrificial layer, wherein the second dielectric layer is formedover the first dielectric layer after the sacrificial layer is removed.18. The method of claim 16, further comprising: forming a passivationlayer over the interconnect structure; and forming a conductive pad overthe passivation layer, wherein the first dielectric layer is formed overthe conductive pad and the passivation layer.
 19. The method of claim16, wherein the bond pad of the semiconductor die has a lateral widththat is less than that of the second conductive material.
 20. The methodof claim 16, wherein the bond pad of the semiconductor die has a lateralwidth that is greater than that of the second conductive material.